Errors of SampleReactiveOAuth2ClientApplicationTests.java Reported When Compiling Spring Boot
Symptom
The message "UnKnownHostException" is displayed when "api.login.yahoo.com" is accessed during the Spring Boot compilation.

Key Process and Cause Analysis
The host is not mapped. Add proxy configurations to solve the problem.
Conclusion and Solution
- Open the SampleReactiveOAuth2ClientApplicationTests.java file.
vim ./spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-reactive-oauth2-client/src/test/java/smoketest/oauth2/client/SampleReactiveOAuth2ClientApplicationTests.java
- Press i to enter the insert mode and modify the file.
- Add the following content below line 18:
import java.util.Properties;

- Insert the following code from line 34:
static { Properties props = System.getProperties(); props.put("http.proxyHost", "127.0.0.1"); props.put("http.proxyPort", "3128"); props.put("https.proxyHost", "127.0.0.1"); props.put("https.proxyPort", "3128"); }In the preceding example, 127.0.0.1 and 3128 indicate the IP address and port number of the proxy host. Replace them with the actual ones.

Run the :set list command to check the format. Spaces are not allowed. Use Tab to indent the code.
- Add the following content below line 18:
- Press Esc, type :wq!, and press Enter to save the file and exit.
- Recompile Spring Boot.
Parent topic: Troubleshooting